Scientists have developed low weight, high-safety components to improve lithium ion batteries, using phosphorus PIN FRs. A publication from Stanford University and SLAC (US National Accelerator Laboratory) proposes to replace the meal foils currently used as current collectors in lithium ion batteries by a sandwich of ultrathin copper (c. 500 nm) and polyimide with 25% TPP (tri phenyl phosphate) PIN flame retardant (9 000 nm). Current collectors today represent 15 – 20 % weight of lithium ion batteries, and though essential are inactive, not contributing to cell capacity. Compared to the thinnest current copper foils, the proposed sandwich collectors enable a 16 – 26% improvement in battery specific energy. The TPP included in the sandwich current collectors is sufficient to considerably improve fire safety of lithium ion cells: a traditional cell burns vigorously and is completely destroyed within 20 seconds of exposure to an open flame, whereas the TPP-sandwich containing cell self-extinguishes within around 6 seconds.
“A new approach boosts lithium-ion battery efficiency and puts out fires, too” https://scienceblog.com/519032/a-new-approach-boosts-lithium-ion-battery-efficiency-and-puts-out-fires-too/ and full article “Ultralight and fire-extinguishing current collectors for high-energy and high-safety lithium-ion batteries”, Y. Ye et al., Nature Energy, vol. 5 Oct. 2020, pp. 786-793 https://doi.org/10.1038/s41560-020-00702-8